[Cognitive assessment of asymptomatic Huntington's disease carriers].

The recent availability of a genetic analysis for the diagnosis of Huntington's disease (HD) allows now for a careful study of presymptomatic stages of the disease. The aim of this study was to see if subtle cognitive deficits could be elicited on formal neuropsychological testing in asymptomatic HD carriers. Thirty-six individuals at risk for HD, applying for genetic assessment, were studied with a cognitive protocol covering attention, memory, visuospatial and prefrontal functions. Gene IT15 analysis revealed an abnormal expansion of (CAG) trinucleotide repeats in 18 subjects, being normal in the remaining 18. The comparison of the neuropsychological performance between both groups did not show significant differences in any of the cognitive domains. These data support that there is no premorbid cognitive impairment in HD, at least recognizable with the current measures of assessment.